I spent a good portion of my life, while I was employed by Digital Chocolate, working on a game called AvaPeeps:FlirtNation. Initially, it was only targeted at the mobile phone market, but it has just been launched as a beta release as a web game.
The game allows you to design an avatar character and send him/her out on dates with other people's avatars. You can send your avatar to different locations to hang out and meet other avatars, coach him/her in what to do on dates, and exchange messages with other peeps.
It was a fun and challenging application to work on, and it will be interesting to see how it does with a web audience. As a member of the team, I spent a lot of time figuring out how to get it to scale up to support millions of users. Hopefully that work will be put to the test.
It's free, so check it out!